Continuous processing of flexible glass ribbon

ABSTRACT

A method of continuously processing glass ribbon having a thickness≤0.3 mm. The method includes providing a glass processing apparatus having a first processing zone, a second processing zone and a third processing zone. The glass ribbon is continuously fed from the first processing zone, through the second processing zone to the third processing zone. The feed rate of the glass ribbon is controlled through each processing zone using a global control device. A first buffer zone is provided between the first processing zone and the second processing zone in which the glass substrate is supported in a first catenary between two, spaced-apart, payoff positions. A second buffer zone is provided between the second processing zone and the third processing zone in which the glass substrate is supported in a second catenary between two, spaced-apart, payoff positions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 15/324518 filed on Jan. 6, 2017 and claims the benefit of priorityunder 35 U.S.C. § 371 of International patent application Ser. No.PCT/US15/39280, filed on Jul. 7, 2015, which in turn, claims the benefitof priority of U.S. Provisional Application Ser. No. 62/021924 filed onJul. 8, 2014, the contents of each of which are relied upon andincorporated herein by reference in their entireties.

TECHNICAL FIELD

The present invention relates to apparatus and methods for continuousprocessing of flexible glass ribbon.

BACKGROUND

Glass processing apparatus are commonly used to form various glassproducts for example LCD sheet glass. Glass substrates in flexibleelectronic applications are becoming thinner and lighter. Glasssubstrates having thicknesses lower than 0.5 mm, for example less than0.3 mm, for example 0.1 mm or even thinner can be desirable for certaindisplay applications, especially portable electronic devices for examplelaptop computers, handheld devices and the like.

Flexible glass substrates, for example glass substrates used in themanufacture of display devices, are often processed in sheet form. Suchprocessing can include, for example, the deposition of thin filmelectronics onto the substrate. Sheet form handling has relatively slowprocessing speeds compared to continuous processes, since sheets must beindividually transported, fixtured, processed and removed. Continuousprocessing of flexible glass substrates in ribbon form can providerelatively faster manufacturing rates. One benefit for a thin glasssubstrate is that the flexibility afforded by the thin ribbon allows itto be used in processes utilizing rolls of the material.

SUMMARY

The present concept involves continuous processing of flexible glassribbon. Continuous processing of flexible glass ribbon can includeconnections among a number of process steps, for example forming,cutting, spooling, etc. Presented herein is a process to actively drivethe flexible glass ribbon at desired locations to maintain tension andshape, control steering, minimize motion and isolate disturbances duringprocessing of the flexible glass ribbon.

One commercial advantage to the present approach is that disturbanceswithin the flexible glass ribbon can be isolated to inhibit thedisturbances from travelling upstream and downstream, possibly affectingother regions where processing is taking place. Motion of the flexibleglass ribbon can be controlled in various processing areas, for example,laser separation.

According to a first aspect, a method of continuous processing offlexible glass ribbon having a thickness of no more than 0.3 mm using aglass processing apparatus, the method comprising:

providing the glass processing apparatus having at least threeprocessing zones including a first processing zone, a second processingzone and a third processing zone;

continuously feeding the flexible glass ribbon from the first processingzone, through the second processing zone to the third processing zone;

controlling feed rate of the flexible glass ribbon through each of thefirst processing zone, second processing zone and third processing zoneusing a global control device;

providing a first buffer zone between the first processing zone and thesecond processing zone in which the flexible glass substrate issupported in a first catenary between two, spaced-apart payoffpositions; and

providing a second buffer zone between the second processing zone andthe third processing zone in which the flexible glass substrate issupported in a second catenary between two, spaced-apart payoffpositions.

According to a second aspect, there is provided the method of aspect 1,further comprising wherein tension within the flexible glass ribbon inthe travel direction is no more than about 1.8 kilograms per meter(kg/m) (about 0.1 pounds per linear inch (pli)) in at least one of thefirst buffer zone and the second buffer zone.

According to a third aspect, there is provided the method of aspect 1 oraspect 2, comprising producing the flexible glass ribbon in the firstprocessing zone using a forming apparatus.

According to a fourth aspect, there is provided the method of aspect 3,wherein the step of producing the flexible glass ribbon includes using afusion draw process.

According to a fifth aspect, there is provided the method of any one ofaspects 1-4, comprising separating an edge of the flexible glass ribbonas the flexible glass ribbon moves by a cutting device within the secondprocessing zone forming a continuous strip of edge trim connected to acentral portion of the flexible glass ribbon.

According to a sixth aspect, there is provided the method of any one ofaspects 1-5, comprising winding the flexible glass ribbon into a roll atthe third processing zone using a winding apparatus.

According to a seventh aspect, there is provided the method of any oneof aspects 1-6, wherein the two, spaced-apart payoff positions of atleast one of the first and second buffer zones are formed using rollers.

According to an eighth aspect, there is provided the method of aspect 7,wherein rotation of at least one of the rollers is controlled by theglobal control device.

According to a ninth aspect, a method of continuous processing offlexible glass ribbon having a thickness of no more than 0.3 mm using aglass processing apparatus including a forming apparatus in a firstprocessing zone, an edge trimming apparatus in a second processing zoneand a winding apparatus in a third processing zone, the methodcomprising:

forming the flexible glass ribbon in the first processing zone andfeeding the flexible glass ribbon though the first processing zone at afirst feed rate;

feeding the flexible glass ribbon through the second processing zonewhile separating an edge of the flexible glass ribbon as the flexibleglass ribbon moves by a cutting device within the second processing zoneforming a continuous strip of edge trim connected to a central portionof the flexible glass ribbon;

feeding the flexible glass ribbon through the third processing zonewhile winding the flexible glass ribbon into a roll;

wherein the first, second and third feed rates are controlled by aglobal control device.

According to a tenth aspect, there is provided the method of aspect 9,further comprising providing a first buffer zone between the firstprocessing zone and the second processing zone in which the flexibleglass substrate is supported in a first catenary between two,spaced-apart payoff positions.

According to an eleventh aspect, there is provided the method of aspect10, further comprising providing a second buffer zone between the secondprocessing zone and the third processing zone in which the flexibleglass substrate is supported in a second catenary between two,spaced-apart payoff positions.

According to a twelfth aspect, there is provided the method of aspect11, wherein tension within the flexible glass ribbon in the traveldirection is no more than about 1.8 kg/m (about 0.1 pli) in at least oneof the first buffer zone and the second buffer zone.

According to a thirteenth aspect, there is provided the method of aspect11, wherein the two, spaced-apart payoff positions of at least one ofthe first and second buffer zones are formed using rollers.

According to a fourteenth aspect, there is provided the method of aspect13, wherein rotation of at least one of the rollers is controlled by theglobal control device.

According to a fifteenth aspect, a glass processing apparatus thatprocesses a flexible glass ribbon having a thickness of no more than 0.3mm comprising:

a forming apparatus in a first processing zone, the forming apparatusconfigured to form the flexible glass ribbon in the first processingzone;

an edge trimming apparatus in a second processing zone, the edgetrimming apparatus configured to separate an edge of the flexible glassribbon as the flexible glass ribbon moves by a cutting device within thesecond processing zone forming a continuous strip of edge trim connectedto a central portion of the flexible glass ribbon;

a winding apparatus in a third processing zone, the winding apparatusconfigured to wind the flexible glass ribbon into a roll;

a first buffer zone between the first processing zone and the secondprocessing zone in which the flexible glass substrate is supported in afirst catenary between two, spaced-apart payoff positions; and

a second buffer zone between the second processing zone and the thirdprocessing zone in which the flexible glass substrate is supported in asecond catenary between two, spaced-apart payoff positions.

According to a sixteenth aspect, there is provided the method of aspect15, further comprising a global control device that controls a feed rateof the flexible glass substrate within the first, second and thirdprocessing zones.

According to a seventeenth aspect, there is provided the method ofaspect 15 or aspect 16, wherein the two, spaced-apart payoff positionsof at least one of the first and second buffer zones are formed usingrollers.

According to an eighteenth aspect, there is provided the method of anyone of aspects 15-17, wherein rotation of at least one of the rollers iscontrolled by the global control device.

According to a nineteenth aspect, there is provided the apparatus of anyone of aspects 15-19, wherein the forming apparatus forms the flexibleglass ribbon using a fusion draw process.

According to a twentieth aspect, there is provided the method orapparatus of any one of aspects 1-20, wherein tension within theflexible glass ribbon in the travel direction is from about 0.9 kg/m toabout 5.4 kg/m (from about 0.05 pli to about 0.3 pli) in at least one ofthe first, second and third processing zones.

According to a twenty-first aspect, there is provided the method orapparatus of any one of claims 1-21, wherein tension within the flexibleglass ribbon in the travel direction is from about 1.4 kg/m to about 2.7kg/m (from about 0.08 pli to about 0.15 pli) in at least one of thefirst, second and third processing zones.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from the description or recognized by practicing theinvention as exemplified in the written description and the appendeddrawings and as defined in the appended claims. It is to be understoodthat both the foregoing general description and the following detaileddescription are merely exemplary of the invention, and are intended toprovide an overview or framework to understanding the nature andcharacter of the invention as it is claimed.

The accompanying drawings are included to provide a furtherunderstanding of principles of the invention, and are incorporated inand constitute a part of this specification. The drawings illustrate oneor more embodiment(s), and together with the description serve toexplain, by way of example, principles and operation of the invention.It is to be understood that various features of the invention disclosedin this specification and in the drawings can be used in any and allcombinations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an embodiment of a flexible glass formingmethod and apparatus;

FIG. 2 is a schematic, detail view of the flexible glass forming processand apparatus of FIG. 1;

FIG. 3 is a schematic, plan view of an embodiment of an edge trimmingmethod and apparatus;

FIG. 4 is a schematic, side view of the edge trimming method andapparatus of FIG. 3;

FIG. 5 is a schematic, plan view of an embodiment of a glass processingapparatus over one half of a width of the flexible glass ribbon that caninclude the flexible glass forming apparatus of FIG. 1, the edgetrimming apparatus of FIG. 3 and a glass winding apparatus; and

FIG. 6 illustrates an embodiment of a glass winding apparatus for use inthe glass processing apparatus of FIG. 5.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation andnot limitation, example embodiments disclosing specific details are setforth to provide a thorough understanding of various principles of thepresent disclosure. However, it will be apparent to one having ordinaryskill in the art, having had the benefit of the present disclosure, thatthe present disclosure may be practiced in other embodiments that departfrom the specific details disclosed herein. Moreover, descriptions ofwell-known devices, methods and materials may be omitted so as not toobscure the description of various principles of the present disclosure.Finally, wherever applicable, like reference numerals refer to likeelements.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another embodiment includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about,” it willbe understood that the particular value forms another embodiment. Itwill be further understood that the endpoints of each of the ranges aresignificant both in relation to the other endpoint, and independently ofthe other endpoint.

Directional terms as used herein—for example up, down, right, left,front, back, top, bottom—are made only with reference to the figures asdrawn and are not intended to imply absolute orientation.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is no way intended thatan order be inferred, in any respect. This holds for any possiblenon-express basis for interpretation, including: matters of logic withrespect to arrangement of steps or operational flow; plain meaningderived from grammatical organization or punctuation; the number or typeof embodiments described in the specification.

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to a “component” includes aspects having two or moresuch components, unless the context clearly indicates otherwise.

Embodiments described herein generally relate to apparatus and methodsfor continuous manufacturing of flexible glass ribbon by activelycontrolling tension and steering of the continuous flexible glass ribbonat locations throughout the process from root to spooler or winder. Anumber of processing zones may be provided within the process wheretension and shape of the continuous flexible glass ribbon can becontrolled independently by isolating the processing zones from oneanother using buffer zones where the flexible glass ribbon hangs in freeloops. Driven mechanisms for example rollers, belts, etc. can be used todeliver tension parallel to the glass travel direction as well astransverse to the glass travel direction.

While glass is generally known as a brittle material, inflexible andprone to scratching, chipping and fracture, glass having a thin crosssection can in fact be quite flexible. Glass in long thin sheets orribbons can be wound and un-wound from rolls, much like paper or plasticfilm.

Maintaining lateral alignment of the glass ribbon as the glass ribbontravels through glass manufacturing equipment may be complicated bymisalignment of components of the glass manufacturing equipment.Further, instabilities, perturbations, vibrations, and transient effectsthat may exist in manufacturing environments or in processing andhandling equipment may cause intermittent or extended misalignment ofthe glass ribbon to occur. In extreme cases, the instabilities,perturbations, vibrations, and transient effects of the glass ribbon maylead to fracture.

Some glass ribbons are processed by continuously separating thickenededge beads from the glass ribbon. During the bead removal process, thethickened edge beads are separated from the glass ribbon and areconveyed down a path different than that of a quality portion of theglass ribbon. The thickened beads impart stress on the glass ribbon atthe point where the glass ribbon is separated from the thickened edgebeads. The relative angle between the glass ribbon and the separatedthickened edge beads affects the stress at the separation point, andmisalignment of the glass ribbon entering the bead separation processcan increase the stress at the separation point, potentially causingribbon breakage or poor edge separation attributes, for example inferioredge strength and edge damage. By using the techniques described herein,some embodiments of glass ribbon achieve an edge strength of at leastabout 100 MPA, for example at least about 200 MPa, at the cut edge afterseparation of the bead.

The apparatus and methods described facilitate continuous processing offlexible glass ribbon by isolating various processing zones from oneanother using free loops (which may also be called buffer zones orcatenaries) in the flexible glass ribbon between processing zones. Theprocessing zones may include forming, edge separation and winding;however, other types of processing zones may be utilized. Further, speedand tension of the flexible glass ribbon may be controlled locallywithin the processing zones using a global control device, for example acomputer that monitors conditions within each of the zones. Suchapparatus and methods can be used to drive the flexible glass ribbon atdesired locations while maintaining tension and shape, controllingsteering, reducing motion and isolating disturbance.

Referring to FIG. 1, an exemplary glass manufacturing apparatus 10 thatincorporates a fusion process to produce a glass ribbon 12 is depicted.The glass manufacturing apparatus 10 may be part of a glass processingapparatus 100 (FIG. 5), as will be described in greater detail below,where a glass ribbon is formed, separated along edges and then rolled ina continuous process. The glass manufacturing apparatus 10 includes amelting vessel 14, a fining vessel 16, a mixing vessel 18 (e.g., a stirchamber), a delivery vessel 20 (e.g., a bowl), a forming apparatus 22and a draw apparatus 24. The glass manufacturing apparatus 10 produces acontinuous glass ribbon 12 from batch materials, first by melting andcombining the batch materials into molten glass, distributing the moltenglass into a preliminary shape, applying tension to the glass ribbon 12to control the dimensions of the glass ribbon 12 as the glass cools andviscosity increases such that the glass ribbon 12 goes through avisco-elastic transition and has mechanical properties that that givethe glass ribbon 12 stable dimensional characteristics.

In operation, batch materials for forming glass are introduced into themelting vessel 14 as indicated by arrow 26 and are melted to form moltenglass 28. The molten glass 28 flows into the fining vessel 16, whereingas bubbles are removed from the molten glass. From the fining vessel16, the molten glass 28 flows into the mixing vessel 18, where themolten glass 28 undergoes a mixing process to homogenize the moltenglass 28. The molten glass 28 flows from the mixing vessel 18 to thedelivery vessel 20, which delivers the molten glass 28 through adowncomer 30 to an inlet 32 and into the forming apparatus 22.

The forming apparatus 22 depicted in FIG. 1 is used in a fusion drawprocess to produce a flexible glass ribbon 46 that has high surfacequality and low variation in thickness. The forming apparatus 22includes an opening 34 that receives the molten glass 28. The moltenglass 28 flows into a trough 36 and then overflows and runs down thesides of the trough 36 in two partial ribbon portions 38, 40 (see FIG.2) before fusing together below the root 42 of the forming apparatus 22.The two partial ribbon portions 38, 40 of the still-molten glass 28rejoin with one another (e.g., fuse) at locations below the root 42 ofthe forming apparatus 22, thereby forming a flexible glass ribbon 46(also referred to as a glass ribbon). The flexible glass ribbon 46 isdrawn downward from the forming apparatus by the draw apparatus 24.While the forming apparatus 22 is shown and described herein implementsa fusion draw process, it should be understood that other formingapparatuses may be used including, without limitation, slot drawapparatuses for example.

As shown in FIG. 1 and as will be described in greater detail below, thedraw apparatus 24 may include a plurality of actively-driven stub rollerpairs 50, 52, each of which include a front-side stub roller 54 and arear-side stub roller 56. The front-side stub roller 54 is coupled to afront-side transmission 58, which is coupled to a front-side motor 60.The front-side transmission 58 modifies the output speed and torque ofthe front-side motor 60 that is delivered to the front-side stub roller54. Similarly, the rear-side stub roller 56 is coupled to a rear-sidetransmission 62, which is coupled to a rear-side motor 64. The rear-sidetransmission 62 modifies the output speed and torque of the rear-sidemotor 64 that is delivered to the rear-side stub roller 56.

Operation of the plurality of stub roller pairs 50, 52 is controlled bya global control device 70 (e.g., a programmable logic controller—PLC)for a variety of conditions including, for example and withoutlimitation, torque applied to the flexible glass ribbon 46 and rate ofrotation of the stub rollers 54, 56. The draw forces applied to theflexible glass ribbon 46 by the plurality of stub roller pairs 50, 52while the flexible glass ribbon 46 is still in a visco-elastic statecause the flexible glass ribbon 46 to pull or stretch, therebycontrolling the dimensions of the flexible glass ribbon 46 bycontrolling the tension applied to the flexible glass ribbon 46 in oneor both the draw and cross-draw directions as the flexible glass ribbon46 translates along the draw apparatus 24, while also imparting motionto the flexible glass ribbon 46.

The global control device 70 may include computer readable instructionsstored in memory 72 and executed by a processor 74 that can determine,among other things, draw tension and speed of the flexible glass ribbon46 provided by the stub roller pairs 50 and 52, for example, using anysuitable sensors that provide feedback to the global control device 70.Further, the computer readable instructions can allow modification ofparameters, for example torque and velocity of the stub roller pairs 50,52 in light of feedback from the sensors. As one example, a stub roller76 may be provided that communicates with the global control device 70to indicate rate of rotation. The rate of rotation of the stub roller 76with the flexible glass ribbon 46 can be used by the global controldevice 70 to determine the extrinsic linear feed rate of the flexibleglass ribbon 46 as the flexible glass ribbon 46 moves thereby. Althoughthere is shown one pair of stub rollers 50 on each side of the ribbon,any suitable number of these type of stub roller pairs may be used,depending upon draw length and desired control. Similarly, although twoof stub roller pairs 52 are shown on each side of the ribbon, anysuitable number of these type of stub roller pairs 52 may be used.

As the flexible glass ribbon 46 is drawn through the draw apparatus 24,the glass has an opportunity to cool. The glass manufacturing apparatus100 having the plurality of stub roller pairs 50, 52 may improve thecontrol and consistency of the cross-draw tension and/or down-drawntension in the area in which the glass ribbon 46 goes through avisco-elastic transformation. This area may be defined as the “settingzone” in which the stress and flatness are set into the glass ribbon 46.Glass manufacturing apparatus 100 that include the plurality of activelydriven stub roller pairs 50, 52 may provide improvements in themanufacturing of flexible glass ribbon 46 as compared to conventionallydesigned manufacturing apparatus that incorporate rollers that extendalong the entire width of the flexible glass ribbon 46. However, incertain situations, manufacturing apparatus that utilize rollers thatextend along the entire width of the flexible glass ribbon 46 may beused.

The global control device 70 may use the draw apparatus 24 to set aglobal master speed for the glass processing apparatus 100 (FIG. 5),while also shaping the flexible glass ribbon 46. Referring to FIG. 3, asnoted above, the glass manufacturing system 10 may be part of the glassprocessing apparatus 100. The flexible glass ribbon 46 is illustratedbeing conveyed through the glass processing apparatus 100, anotherportion of which is illustrated by FIG. 3. The flexible glass ribbon 46may be conveyed in a continuous fashion from the glass manufacturingsystem 10 (FIG. 1) through the glass processing apparatus 100. Theflexible glass ribbon 46 includes a pair of opposed first and secondedges 102 and 104 that extend along a length of the flexible glassribbon 46 and a central portion 106 that spans between the first andsecond edges 102 and 104. In some embodiments, the first and secondedges 102 and 104 may be covered in a pressure sensitive adhesive tape108 that is used to protect and shield the first and second edges 102and 104 from contact. The tape 108 may be applied to one or both of thefirst and second edges 102 and 104 as the flexible glass ribbon 46 movesthrough the apparatus 100. In other embodiments, the adhesive tape 108may not be used. A first broad surface 110 and an opposite, second broadsurface 112 also spans between the first and second edges 102 and 104,forming part of the central portion 106.

In embodiments where the flexible glass ribbon 46 is formed using a downdraw fusion process, the first and second edges 102 and 104 may includebeads 114 and 116 with a thickness T₁ that is greater than a thicknessT₂ within the central portion 106. The central portion 106 may be“ultra-thin” having a thickness T₂ of about 0.3 mm or less including butnot limited to thicknesses of, for example, about 0.01-0.05 mm, about0.05-0.1 mm, about

0.1-0.15 mm and about 0.15-0.3 mm, although flexible glass ribbons 46with other thicknesses may be formed in other examples.

The flexible glass ribbon 46 is conveyed through the apparatus 100 usinga conveyor system 120 that is controlled by the global control device70. Lateral guides 122 and 124 may be provided to orient the flexibleglass ribbon 46 in the correct lateral position relative to the machineor travel direction 126 of the flexible glass ribbon 46. For example, asschematically shown, the lateral guides 122 and 124 may include rollers128 that engage the first and second edges 102 and 104. Opposed forces130 and 132 may be applied to the first and second edges 102 and 104using the lateral guides 122 and 124 that help to shift and align theflexible glass ribbon 46 in the desired lateral orientation in thetravel direction 126.

The glass processing apparatus 100 can further include a cutting zone140 downstream from a bend axis 142 about which the flexible glassribbon 46 may be bent. In one example, the apparatus 100 may include acutting support member configured to bend the flexible glass ribbon 46in the cutting zone 140 to provide a bent target segment 144 with a bentorientation. Bending the target segment 144 within the cutting zone 140can help stabilize the flexible glass ribbon 46 during the cuttingprocedure. Such stabilization can help prevent buckling or disturbingthe flexible glass ribbon profile during the procedure of separating atleast one of the first and second edges 102 and 104 from the centralportion 106 of the flexible glass ribbon 46.

Providing the bent target segment 144 in the cutting zone 140 canincrease the rigidity of the flexible glass ribbon 46 throughout thecutting zone 140. As such, as shown in FIG. 3, optional lateral guides150, 152 can engage the flexible glass ribbon 46 in a bent conditionwithin the cutting zone 140. Forces 154 and 156 applied by the lateralguides 150 and 152 are therefore less likely to buckle or otherwisedisturb the stability of the glass ribbon profile when laterallyaligning as the flexible glass ribbon 46 passes through the cutting zone140. In other embodiments, a bent target segment may not be employed andthe flexible glass ribbon 46 may be maintained substantially flat in thecutting zone.

As set forth above, providing the bent target segment 144 in a bentorientation within the cutting zone 140 can help stabilize the flexibleglass ribbon 46 during the cutting procedure. Such stabilization canhelp prevent buckling or disturbing the glass ribbon profile during theprocedure of separating at least one of the first and second edges 102and 104. Moreover, the bent orientation of the bent target segment 144can increase the rigidity of the bent target segment 144 to allowoptional fine tune adjustment of the lateral orientation of the benttarget segment 144. As such, the flexible glass ribbon 46 can beeffectively stabilized and properly laterally oriented withoutcontacting the first and second broad surfaces of the central portion106 during the procedure of separating at least one of the first andsecond edges 102 and 104.

The apparatus 100 can further include a wide range of edge trimmingapparatus configured to separate the first and second edges 102 and 104from the central portion 106 of the flexible glass ribbon 46 in acontinuous fashion. In one example, as shown in FIG. 4, one example edgetrimming apparatus 170 can include an optical delivery apparatus 172 forirradiating and therefore heating a portion of the upwardly facingsurface of the bent target segment 144. In one example, optical deliveryapparatus 172 can comprise a cutting device for example the illustratedlaser 174 although other radiation sources may be provided in furtherexamples. The optical delivery apparatus 172 can further include acircular polarizer 176, a beam expander 178, and a beam shapingapparatus 180.

The optical delivery apparatus 172 may further comprise optical elementsfor redirecting a beam of radiation (e.g., laser beam 182) from theradiation source (e.g., laser 174), for example mirrors 184, 186 and188. The radiation source can comprise the illustrated laser 174configured to emit a laser beam having a wavelength and a power suitablefor heating the flexible glass ribbon 46 at a location where the beam isincident on the flexible glass ribbon 46. In one embodiment, laser 174can comprise a CO₂ laser although other laser types may be used infurther examples.

As further shown in FIG. 4, the example edge trimming apparatus 170 canalso include a coolant fluid delivery apparatus 192 configured to coolthe heated portion of the upwardly facing surface of the bent targetsegment 144. The coolant fluid delivery apparatus 192 can comprise acoolant nozzle 194, a coolant source 196 and an associated conduit 198that may convey coolant to the coolant nozzle 194.

In one example, a coolant jet 200 comprises water, but may be anysuitable cooling fluid (e.g., liquid jet, gas jet or a combinationthereof) that does not stain or damage the upwardly facing surface ofthe bent target segment 144 of the flexible glass ribbon 46. The coolantjet 200 can be delivered to a surface of the flexible glass ribbon 46 toform a cooling zone 202. As shown, the cooling zone 202 can trail behinda radiation zone 204 to propagate an initial crack (FIG. 3).

The combination of heating and cooling with the optical deliveryapparatus 172 and the coolant fluid delivery apparatus 192 caneffectively separate the first and second edges 102 and 104 from thecentral portion 106 while minimizing or eliminating undesired residualstress, microcracks or other irregularities in the opposed edges 206,208 of the central portion 106 that may be formed by other separatingtechniques. Moreover, due to the bent orientation of the bent targetsegment 144 within the cutting zone 140, the flexible glass ribbon 46can be positioned and stabilized to facilitate precise separating of thefirst and second edges 102 and 104 during the separating process. Stillfurther, due to the convex surface topography of the upwardly facingconvex support surface, the continuous strips of edge trim 210 and 212can immediately travel away from the central portion 106, therebyreducing the probability that the first and second edges 102 and 104will subsequently engage (and therefore damage) the first and secondbroad surfaces and/or the high quality opposed edges 206, 208 of thecentral portion 106. The central portion 106 may then be wound into aroll using a winding apparatus 270.

Referring to FIG. 5, as can be appreciated, the various processes (e.g.,forming, edge separating and rolling) may introduce instabilities,perturbations, vibrations, and transient effects to the flexible glassribbon 46 as the flexible glass ribbon 46 travels through the glassprocessing apparatus 100. As noted above, FIG. 5 is a schematic view ofone half of a glass ribbon, whereupon it will be appreciated that asimilar arrangement will exist on the right half of this figure but, inthe interest of simplifying the discussion, is not shown. To reduce theupstream and/or downstream impact of any instabilities, perturbations,vibrations, and transient effects, the glass processing apparatus may bedivided into a number of isolated processing zones, each zonecorresponding to one or more different processes. In the illustratedexample shown schematically, processing zone A includes a flexible glassribbon forming process, processing zone B includes a flexible glassribbon cutting process and processing zone C includes a flexible glassribbon winding process, where the processes within the processing zonesmay be similar to any of the processes described above.

Processing zone A may include a forming apparatus 230, similar to or thesame as the forming apparatus 22 described above with reference to FIG.1, where a fusion draw process is used to produce the flexible glassribbon 46. Stability of the flexible glass ribbon 46 within processingzone A may be achieved through use of driven rollers (e.g., multipleelevations of driven roller pairs) represented by elements 234, 235 and236 applying adjustable mechanical tensions in the direction of travelshown by arrow 238 {for example, from about 0.36, kilograms per meter(kg/m) to about 8.9 kg/m (0.02 pounds per linear inch (pli) to about 0.5pli), for example from about 0.9 kg/m to about 5.4 kg/m (from about 0.05pli to about 0.3 pli), for example from about 1.4 kg/m to about 2.7 kg/m(from about 0.08 pli to about 0.15 pli)} as well as cross-directiontension, if needed. One or more of the driven rollers 234, 235 and 236(e.g., driven roller 235) may also be used by the global control device70 to set a global master speed, e.g., from about 84 millimeters persecond (mm/s) to about 255 mm/s (e.g., from about 200 inches per minute(ipm) to about 600 ipm) of the flexible glass ribbon 46 within at leastprocessing zone A.

A buffer zone 240 is provided between processing zone A and processingzone B for process isolation between the processing zones A and B.Within the buffer zone 240, the flexible glass ribbon 46 may be held ina free loop 242 (FIG. 4) and may hang in a catenary between two pay offpositions defined by driven rollers 244 and 246 (more particularly, thelocation where the flexible glass ribbon 46 releases from the drivenrollers 244 and 246). For example, rollers 244 and 246 may be from 4meters to 12 meters apart, for example, from about 1.5 meters to about7.5 meters apart, to allow use of a number of cullet chutes, loop outmitigation devices, etc. Between these two pay off positions theflexible glass ribbon 46 is not pulled tight and hangs under its ownweight. For example, the tension in the flexible glass ribbon 46 can beno more than about 1.8 kg/m (about 0.1 pli), for example from about 0.18kg/m to about 1.8 kg.m (from about 0.01 pli to about 0.1 pli) within thefree loop 242.

The free loop 242 shape can self-adjust depending on the amount of pullforce and gravitational force within the buffer zone 240. The free loop242 can accommodate more or less flexible glass ribbon 46 by adjustingthe free loop 242 shape, which is controlled by tension within the freeloop 242. The buffer zone 240 can serve as an accumulator of errorbetween processing zones A and B. The buffer zone 240 can accommodateerrors for example path length differences due to velocity, twist orshape variance due to strain mismatch and machine misalignment errors.In some embodiments, a loop sensor 247, for example an ultrasonic oroptical sensor, may be provided to maintain a preselected loop height.In some embodiments, a tension sensor (e.g., a strain gauge) may beprovided to measure tension within the flexible glass ribbon 46. In someembodiments, the drives driving the rollers may have an in-line torquetransducer used to measure tension within the flexible glass ribbon 46.The sensors may provide real-time information to the global controldevice 70, which can adjust the speed and/or tension of the drivenrollers 244 and 246 based on the information.

Processing zone B may include an edge trimming apparatus 250, similar toor the same as the edge trimming apparatus 170 described above withreference to FIGS. 3 and 4, where first and second edges (only edge 102is shown in FIG. 5) are separated from central portion 106 of theflexible glass ribbon 46. Stability of the flexible glass ribbon 46within the processing zone B may be achieved through use of drivenrollers represented by elements 252 and 254 a and 254 b. Roller 246 maybe driven during initial threading of the flexible glass ribbon 46, butmay thereafter be idle for cross-direction steering or guiding of theflexible glass ribbon 46 within the processing zone B. The drivenrollers 252, 254 a and 254 b may be used to provide tension {forexample, from about 0.36, kilograms per meter to about 8.9 kg/m (0.02pounds per linear inch to about 0.5 pli), for example from about 0.9kg/m to about 5.4 kg/m (from about 0.05 pli to about 0.3 pli), forexample from about 1.4 kg/m to about 2.7 kg/m (from about 0.08 pli toabout 0.15 pli)} within the cutting zone 140 (FIG. 3) and to controlsteering of the flexible glass ribbon 46 and first and second edges(only edge 102 is shown) as they are separated from the central portion106. One or more of the driven rollers 252 and 245 b (e.g., drivenroller 254 b) may be used by the global control device 70 to set a localmaster speed {e.g., from about 84 mm/s to about 255 mm/s (e.g., fromabout 200 ipm to about 600 ipm)} within the processing zone B. It shouldbe noted that speed variance between the global and local master speedswithin the zones A, B and C, if any, is to allow for tension managementwithin the flexible glass ribbon 46, as well as absolute errormanagement.

Another buffer zone 260 is provided between processing zone B andprocessing zone C for process isolation between the processing zones Band C. Within the buffer zone 260, the flexible glass ribbon 46 may beheld in a free loop 262 (FIG. 4) and may hang in a catenary between twopay off positions defined by driven rollers 254 b and 264). For example,rollers 254 b and 264 may be from about 4 meters to about 12 metersapart, for example, from about 1.5 meters to about 7.5 meters apart, toallow use of a number of cullet chutes, loop out mitigation devices,etc. Between these two pay off positions the flexible glass ribbon 46 isnot pulled tight and hangs under its own weight. For example, thetension in the flexible glass ribbon 46 can be no more than about 1.8kg/m (about 0.1 pli), for example from about 0.18 kg/m to about 1.8 kg/m(from about 0.01 pli to about 0.1 pli) within the free loop 262.

The free loop 262 shape can self-adjust depending on the amount of pullforce and gravitational force within the buffer zone 260. The free loop262 can accommodate more or less flexible glass ribbon 46 by adjustingthe free loop 262 shape, which is controlled by tension within the freeloop 262. The buffer zone 260 can serve as an accumulator of errorbetween processing zones B and C. The buffer zone 260 can accommodateerrors for example path length differences due to velocity, twist orshape variance due to strain mismatch and machine misalignment errors.In some embodiments, a loop sensor 266, for example an ultrasonic oroptical sensor, may be provided to maintain a preselected loop height.In some embodiments, a tension sensor (e.g., a strain gauge) may beprovided to measure tension within the flexible glass ribbon 46. Thesensors may provide real-time information to the global control device70, which can adjust the speed and/or tension of the driven rollers 254b and 264 based on the information.

Processing zone C may include a winding apparatus 270, where the centralportion 106 of the flexible glass ribbon 46 is wound into a roll.Stability of the flexible glass ribbon 46 within the processing zone Cmay be achieved through use of driven rollers represented by elements268, 274, 276 and 278. Roller 264 may be driven during initial threadingof the flexible glass ribbon 46, but may thereafter be idle forcross-direction steering or guiding of the flexible glass ribbon 46within the processing zone C. The driven rollers 268, 274, 276 and 278may be used to provide tension (e.g., from about 2.7 kg/m to about 6.3kg/m (from about 0.15 pli to about 0.35 pli)) within processing zone Cand to control steering of the flexible glass ribbon 46. In someembodiments, for example, when a driven roller is used to apply tensionto the glass as it is being rolled, due to increasing diameter of theglass roll, torque from that driven roller may be adjusted to result intension (in the flexible glass ribbon being rolled) decreasing fromabout 6.3 kg/m to about 2.7 kg/m (from about 0.35 pli to about 0.15 pli)as a linear ramp. One or more of the driven rollers 268, 274, 276 and278 (e.g., driven rollers 274 and 278) may be used to by the globalcontrol device 70 to set a local master speed {e.g., from about 84 mm/sto about 255 mm/s (e.g., from about 200 ipm to about 600 ipm)} withinthe processing zone C.

As one example, FIG. 6 illustrates schematically a winding apparatus 270for rolling the central portion 106 of the flexible glass ribbon 46together with an interleaving material 272. The driven rollers 254 b and264 may be used for guiding the central portion 106 of the flexibleglass ribbon 46 and driven rollers 280 may be used for guiding theinterleaving material 272. The driven rollers 254 b, 264 and 280 guidethe flexible glass ribbon 46 and the interleaving material 272 to a roll282, where they may be wound together. The free loop 262 isolatesprocessing zone C from processing zone B and compensates for differences(for example, as when rolling speed is varied at roll change over) inthe flexible glass ribbon speeds between the upstream and rollingprocesses. In some embodiments, a surface protective film may be appliedto one or both broad surfaces of the central portion 106 of the flexibleglass ribbon 46.

The above-described methods and apparatus for continuous manufacturingof flexible glass ribbon can provide ultra-thin flexible glass ribbonwhile maintaining precise flexible glass ribbon position management ineach of the processing zones A-C (e.g., forming, cutting, spooling,etc.). As a moving body, the flexible glass ribbon can travel along apre-defined direction, aligned with the various processing apparatus.Tension within the flexible glass ribbon can be adequate and conform tothe needs of each of the processing steps within each of the processingzones. The processing zones A-C and their respective process steps canbe isolated from process steps of the other processing zones using thebuffer zones and free loops. The global control device can controltension and velocity locally within each of the processing zones andglobally using real-time feedback from the various tension, speed andposition sensors located within the processing zones.

The above-described methods and apparatus for continuous manufacturingof flexible glass ribbon can provide a robust management system withactive steering, tension control and disturbance isolation to produceultra-thin flexible glass spools. For example, the spools may include aribbon having thicknesses ranging from about 200 microns to about 50microns and ribbon widths ranging from about 1000 mm to about 3000 mm. Aglobal architecture can be provided to stabilize the flexible glassribbon via creation of three local zones and two isolation or bufferzones there between. In some embodiments, there may be one buffer zonebetween each adjacent local zone, each local zone corresponding to adifferent process. In the above-described example, a buffer zone isprovided between flexible glass forming and edge or bead separation, andanother buffer zone is provided between edge or bead separation andspooling. Within each of the processing zones, the flexible glass ribbonforces can be independently controlled by the global control device bybalancing the pull force from the drive system within that zone and theinternal force on the flexible glass ribbon from upstream and downstreamprocesses. Within each of the processing zones, tension within theflexible glass ribbon can be maintained at a constant or nearly constantlevel, which can deliver consistent product attributes for example glassthickness, edge strength and spool quality.

It should be emphasized that the above-described embodiments of thepresent invention, particularly any “preferred” embodiments, are merelypossible examples of implementations, merely set forth for a clearunderstanding of various principles of the invention. Many variationsand modifications may be made to the above-described embodiments of theinvention without departing substantially from the spirit and variousprinciples of the invention. All such modifications and variations areintended to be included herein within the scope of this disclosure andthe following claims.

1. A method of continuous processing of a flexible glass ribbon having acentral portion and an edge portion, and having a thickness of no morethan 0.3 mm, the method comprising: providing a glass processingapparatus having at least three processing zones including a firstprocessing zone, a second processing zone, and a third processing zone;continuously feeding at least the central portion of the flexible glassribbon from the first processing zone having a first feed rate, throughthe second processing zone having a second feed rate to the thirdprocessing zone having a third feed rate; independently controlling thefirst, the second, and the third feed rates using a global controldevice; controlling a global master feed rate using the global controldevice; providing a first buffer zone between the first processing zoneand the second processing zone in which the flexible glass ribbon issupported in a first catenary between a first set of two, spaced-apartpayoff positions; and providing a second buffer zone between the secondprocessing zone and the third processing zone in which the centralportion of the flexible glass ribbon is supported in a second catenarybetween a second set of two, spaced-apart payoff positions.
 2. Themethod of claim 1, wherein the global master feed rate is different thanat least one of the first feed rate, the second feed rate, and the thirdfeed rate.
 3. The method of claim 1, wherein a tension value for theflexible glass ribbon is controlled as a function of a speed variancebetween the global master feed rate and at least one of the first feedrate, the second feed rate, and the third feed rate.
 4. The method ofclaim 1, wherein tension within the central portion of the flexibleglass ribbon in a travel direction is no more than about 1.8 kg/m in atleast one of the first buffer zone and the second buffer zone.
 5. Themethod of claim 1, wherein tension within the central portion of theflexible glass ribbon in a travel direction is from about 0.9 kg/m toabout 5.4 kg/m in at least one of the first, second, and thirdprocessing zones.
 6. The method of claim 1, wherein tension within thecentral portion of the flexible glass ribbon in a travel direction isfrom about 1.4 kg/m to about 2.7 kg/m in at least one of the first,second, and third processing zones.
 7. The method of claim 1 comprisingproducing the flexible glass ribbon in the first processing zone using aforming apparatus.
 8. The method of claim 7, wherein the step ofproducing the flexible glass ribbon includes using a fusion drawprocess.
 9. The method of claim 1 comprising separating the edge portionfrom the central portion of the flexible glass ribbon as the flexibleglass ribbon moves by a cutting device within the second processing zonethereby forming a continuous strip of edge trim.
 10. The method of claim1 comprising winding the central portion of the flexible glass ribboninto a roll at the third processing zone using a winding apparatus. 11.The method of claim 1, wherein at least one of the first or the secondset of two, spaced-apart payoff positions are formed using rollers. 12.The method of claim 11, wherein a rotation of at least one of therollers of the at least one of the first or the second set of two,spaced-apart payoff positions is controlled by the global controldevice.
 13. A method of continuous processing of flexible glass ribbonhaving a central portion and an edge portion, and having a thickness ofno more than 0.3 mm, the continuous processing using a glass processingapparatus including a forming apparatus in a first processing zone, anedge trimming apparatus in a second processing zone, and a windingapparatus in a third processing zone, the method comprising: forming theflexible glass ribbon in the first processing zone and feeding theflexible glass ribbon though the first processing zone at a first feedrate; feeding at least the central portion of the flexible glass ribbonthrough the second processing zone at a second feed rate whileseparating the edge portion from the central portion of the flexibleglass ribbon as the flexible glass ribbon moves by a cutting devicewithin the second processing zone thereby forming a continuous strip ofedge trim; feeding the central portion of the flexible glass ribbonthrough the third processing zone at a third feed rate while winding thecentral portion of the flexible glass ribbon into a roll; wherein thefirst, the second, and the third feed rates are controlled independentlyby a global control device, and wherein a global master feed rate iscontrolled by the global control device.
 14. The method of claim 13,wherein the global master feed rate is different than at least one ofthe first feed rate, the second feed rate, and the third feed rate. 15.The method of claim 13, wherein a tension value for the flexible glassribbon is controlled as a function of a speed variance between theglobal master feed rate and at least one of the first feed rate, thesecond feed rate, and the third feed rate.
 16. The method of claim 13further comprising providing a first buffer zone between the firstprocessing zone and the second processing zone in which the flexibleglass ribbon is supported in a first catenary between a first set oftwo, spaced-apart payoff positions.
 17. The method of claim 16 furthercomprising providing a second buffer zone between the second processingzone and the third processing zone in which the central portion of theflexible glass ribbon is supported in a second catenary between a secondset of two, spaced-apart payoff positions.
 18. The method of claim 17,wherein tension within the central portion of the flexible glass ribbonin a travel direction is no more than about 1.8 kg/m in at least one ofthe first buffer zone and the second buffer zone.
 19. The method ofclaim 17, wherein at least one of the first or the second set of two,spaced-apart payoff positions are formed using rollers.
 20. The methodof claim 19, wherein a rotation of at least one of the rollers of the atleast one of the first or the second set of two, spaced-apart payoffpositions is controlled by the global control device.
 21. A glassprocessing apparatus that processes a flexible glass ribbon having acentral portion and an edge portion, and having a thickness of no morethan 0.3 mm comprising: a forming apparatus in a first processing zone,the forming apparatus configured to form the flexible glass ribbon inthe first processing zone; an edge trimming apparatus in a secondprocessing zone, the edge trimming apparatus configured to separate theedge portion from the central portion of the flexible glass ribbon asthe flexible glass ribbon moves by a cutting device within the secondprocessing zone thereby forming a continuous strip of edge trim; awinding apparatus in a third processing zone, the winding apparatusconfigured to wind the central portion of the flexible glass ribbon intoa roll; a first buffer zone between the first processing zone and thesecond processing zone in which the flexible glass ribbon is supportedin a first catenary between a first set of two, spaced-apart payoffpositions; a second buffer zone between the second processing zone andthe third processing zone in which the central portion of the flexibleglass ribbon is supported in a second catenary between a second set oftwo, spaced-apart payoff positions; and a global control device thatindependently controls, for at least the central portion of the flexibleglass substrate, a first feed rate through the first processing zone, asecond feed rate through the second processing zone, and a third feedrate through the third processing zone, wherein the global controldevice controls a global master feed rate.
 22. The method of claim 21,wherein the global master feed rate is different than at least one ofthe first feed rate, the second feed rate, and the third feed rate. 23.The method of claim 21, wherein a tension value for the flexible glassribbon is controlled as a function of a speed variance between theglobal master feed rate and at least one of the first feed rate, thesecond feed rate, and the third feed rate.
 24. The glass processingapparatus of claim 21, wherein at least one of the first or the secondset of two, spaced-apart payoff positions are formed using rollers. 25.The glass processing apparatus of claim 24, wherein a rotation of atleast one of the rollers of the at least one of the first or the secondset of two, spaced-apart payoff positions is controlled by the globalcontrol device.
 26. The glass processing apparatus of claim 21, whereinthe forming apparatus is configured to form the flexible glass ribbonusing a fusion draw process.
 27. The method of claim 1 wherein at leastone of the first, the second, and the third feed rates is adjusted bythe global control device based on an input signal from a sensor. 28.The method of claim 27 wherein the sensor is a tension sensor selectedfrom the group consisting of a strain gauge, a torque transducer, andcombinations thereof.
 29. The method of claim 27 wherein the sensor is atension sensor and is located so as to measure tension in the centralportion of the flexible glass ribbon in either the first or the secondcatenary.
 30. The method of claim 27 wherein the sensor comprises afirst sensor and a second sensor, wherein the first and second sensorsare unalike, and wherein each of the first and second sensor is selectedfrom the group consisting of a tension sensor, a speed sensor, and aposition sensor.
 31. The method of claim 1 wherein the third feed rateis adjusted by the global control device based on an input signal from atension sensor located so as to measure tension in the central portionof the flexible glass ribbon in the second catenary.
 32. The method ofclaim 31 wherein the global control device drives a roller in the thirdprocessing zone such that the measured tension in the central portion ofthe flexible glass ribbon is decreased linearly from a first value to asecond value.
 33. The method of claim 13 wherein at least one of thefirst, the second, and the third feed rates is adjusted by the globalcontrol device based on an input signal from a sensor.
 34. The method ofclaim 33 wherein the sensor is a tension sensor selected from the groupconsisting of a strain gauge, a torque transducer, and combinationsthereof.
 35. The method of claim 33 wherein the sensor is a tensionsensor and is located so as to measure tension in the central portion ofthe flexible glass ribbon in either the first or the second catenary.36. The method of claim 33 wherein the sensor comprises a first sensorand a second sensor, wherein the first and second sensors are unalike,and wherein each of the first and second sensor is selected from thegroup consisting of a tension sensor, a speed sensor, and a positionsensor.
 37. The method of claim 13 wherein the third feed rate isadjusted by the global control device based on an input signal from atension sensor located so as to measure tension in the central portionof the flexible glass ribbon in the second catenary.
 38. The method ofclaim 37 wherein the global control device drives a roller in the thirdprocessing zone such that the measured tension in the central portion ofthe flexible glass ribbon is decreased linearly from a first value to asecond value.
 39. The glass processing apparatus of claim 21 wherein atleast one of the first, the second, and the third feed rates is adjustedby the global control device based on an input signal from a sensor. 40.The glass processing apparatus of claim 39 wherein the sensor is atension sensor selected from the group consisting of a strain gauge, atorque transducer, and combinations thereof.
 41. The glass processingapparatus of claim 39 wherein the sensor is a tension sensor and islocated so as to measure tension in the central portion of the flexibleglass ribbon in either the first or the second catenary.
 42. The glassprocessing apparatus of claim 39 wherein the sensor comprises a firstsensor and a second sensor, wherein the first and second sensors areunalike, and wherein each of the first and second sensor is selectedfrom the group consisting of a tension sensor, a speed sensor, and aposition sensor.
 43. The glass processing apparatus of claim 21 whereinthe third feed rate is adjusted by the global control device based on aninput signal from a tension sensor located so as to measure tension inthe central portion of the flexible glass ribbon in the second catenary.44. The glass processing apparatus of claim 43 wherein the globalcontrol device drives a roller in the third processing zone such thatthe measured tension in the central portion of the flexible glass ribbonis decreased linearly from a first value to a second value.